


Haikyu Character's Sister Headcanon

by shifter7



Category: Haikyuu!!
Genre: F/M, Fluff, Protective Siblings, Sarcasm, Short One Shot, Siblings
Language: English
Status: In-Progress
Published: 2020-07-25
Updated: 2020-08-20
Packaged: 2021-03-04 22:08:37
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 6
Words: 3,080
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25403614
Author URL: https://archiveofourown.org/users/shifter7/pseuds/shifter7
Summary: Sister headcanon of Haikyu's characters.I promise there are only fluff and funny scenarios. (ﾉ◕ヮ◕)ﾉ*:･ﾟ✧
Relationships: Bokuto Koutarou/Reader, Kageyama Tobio/Reader, Kuroo Tetsurou/Reader, Miya Atsumu/Miya Osamu/Reader, Oikawa Tooru/Reader, Tanaka Ryuunosuke/Reader, Tendou Satori/Reader
Comments: 12
Kudos: 202





	1. Oikawa Tooru

**Author's Note:**

> This one shot is inspired by [Don't Look Back, the sister headcanon of Oikawa](https://archiveofourown.org/works/24999745/chapters/60533485) by [edensgarden](https://archiveofourown.org/users/edensgarden)  
> 

  * Oikawa's sister is totally opposite of him. While he is confident, loud, and sporty, his sister is all shy, timid, quiet, and clumsy. Although they don't look alike, but like Oikawa is handsome, Y/N is just as beautiful. Because you know, genes. So guess what? Oikawa is super protective of her **ALL THE TIMES**. 
  * Y/N is two years younger than him. And a lot shorter than him. So often Oikawa would use her head as an armrest, every time she would pout and say something like “Nii-chan~ this is why I can't get any taller ” while looking at him with those puppy eyes. Oikawa would be like my baby imouto is so damn adorable, then hug her so tight that she almost gasping for air and struggle to get away. When she finally managed to get away from Oikawa's ~~suffocating~~ embrace, she will silently look at him with flushed face and teary eyes. Oikawa would totally squeal and be thinking that Y/N is so cute I must protect her at all cost then hug her tightly again. The cycle repeats.
  * The team (except Iwaizumi) didn't know Oikawa has a sister until one day Y/N's club activity finished earlier and decided to go to the gym and wait for Oikawa to go home together.
  * When she opens the gym's door, ~~unfortunately~~ they are having a short water break, all eyes are on her. Her face instantly went tomato-red because she is not used to people staring at her. Before everyone can see Y/N's face clearly, Oikawa quickly runs to her and covers her entire body with his body to hide her from his teammates because only he and Iwaizumi can see Y/N's angelic, lovely, sweet, adorable, cute face.
  * "Nii-chan, can I wait for you here? I don't wanna go home alone today." Oikawa's heart breaks a little listening to Y/N's quiet and soft voice. Of course, he will let her wait here, but at the same time, he is thinking about how to cover her face ~~because his teammates don't deserve to see your beautiful face~~
  * "What are you doing, trashykawa?" "Captain, who is she?" "Senpai, is she your girlfriend?" 
  * When you heard Iwaizumi's voice, you peek from Oikawa's body to look for him. Iwaizumi is basically your second brother (more dependable and mature brother than Oikawa actually). You smile and wave your hand at him to greet him.
  * Everyone was like "Is it angel I just saw?"
  * Ohh and our mad dog chan, Kyoutani actually blushed.
  * "Y/N." Iwaizumi walks toward them, intended to drag Oikawa back to the court. But Oikawa is like "No~ Iwa-chan~ They can't see Y/N's beautiful face, they don't deserve to…. Ouch, Iwa-chan why are you hitting me again?" Y/N blushed harder after listening to her brother, covering her face with her hands while mumbling "Nii-chan, please don't embarrass me."
  * Well, after this incident, Y/N is forced by Oikawa to wait for him at the gym to finish his practice because after all these times ~~effort~~ to hide your existence from his teammate just gone. He might as well enjoy the chance to show off how good his volleyball skill to his sister. More importantly, he can spend more time with Y/N, since they are going home together now.
  * Kyoutani actually tried to ask you for your number. But failed miserably every time because Oikawa will scream running to you and literally carry you away from him.
  * Oikawa secretly knows all the passwords of your social media accounts because he is a ~~creepy~~ protective brother. He has to make sure no weirdo is bothering his precious Y/N right?
  * Oikawa would purposely put your stuff at the top cabinet just so when you need it you will ask for his help, and he will definitely ask for a reward like a kiss on his cheek or make you say something embarrassing like "Tooru is the best nii-chan, meow♡" 



Extra  
You have a secret crush on Ushijima because you think he is absolutely attractive. Which made Oikawa dislikes Ushijima more because he knew about it. If Oikawa has to choose who could be with you, no doubt that person should be Iwaizumi. So he's been trying to match you with Iwaizumi all these years, but as oblivious as you are, you only think that your brother is just trying to get you to befriend with his best friend, eventually you considered Iwaizumi as another big brother. You have accidentally called Iwaizumi as Onii-chan instead of Hajime kun once. Which made Iwaizumi laughed so hard, you wished the ground literally opened up and swallowed you.

**Notes for the Chapter:**

> Okay, so this is my first work, please be nice to me (´;ω;`)  
> Any comments and suggestions are welcome.


	2. Kuroo Tetsurou

  * Y/N is just as sassy as Kuroo. Never called him nii-chan properly, instead you like to call him funny names like bedhead nii-chan, giant nii-chan, captain nii-chan and more.
  * Basically, the female version of Kenma, except that you suck at sports. Regular gaming teammate with Kenma.
  * Didn't join any club, so you either study at the library while waiting for Kuroo to finish practice or wait for him at the gym.
  * At first, the team thought you are Kuroo's girlfriend because you two don't look alike. As you are way shorter than him, and you don't have bedhead lol
  * When Lev asked whether you are Kuroo's girlfriend you sneered, making Kuroo said “Hey, Y/N. What's with that face, I'm not that bad okay?”
  * Love wearing Kuroo's clothes like jacket and hoodie, because they are so warm and comfy. Kuroo would always complain, but you would say something like feel free to wear my clothes as well *wink. Because you know they are way too small for him.
  * Also, you often go shopping with him, basically you guys choose each other's clothes. Even went to lingerie store together. At first, he refused but he was like senpai tell me more about it after you told him it's useful in future when he has a girlfriend, wouldn't want him choosing ugly and uncomfortable lingerie for his girlfriend. Well, tbh you just want him to pay for your lingerie. *evil smirks
  * Tried to fix his bedhead before, but his bedhead is unfixable.
  * You trained Kuroo to become a master of braiding hair because you are too lazy to braid your hair.
  * A bigger science nerd than Kuroo. You're the one who got him became a science nerd actually.



Extra

You are Bokuto's bff, and have a secret group chat along with Kenma, mainly posting Kuroo funny photos and making him into memes.

**Notes for the Chapter:**

> Lingerie is expensive. _:(´□`」 ∠):_


	3. Kageyama Tobio

  * Basically, a female version of Kageyama in appearance. Thus, the nickname, Ice Princess, because you have the resting bitch face like your brother.
  * Went to Shiratorizawa because unlike your brother, the utter volleyball idiot, you are smart. Sometimes, you will help him to prepare his exam, though you're one year younger than him.
  * Hinata was afraid of you because you look as intimidating as Kageyama. Plus, you are taller than Hinata.
  * The team found out that Kageyama can be quite talkative and smile like normal people do (not like the creepy forced smile he did before) when you are with him.
  * He will make video call to you almost every day to check with you since you are living at Shiratorizawa dorm.
  * "Y/N, how's your day? Are you coming home this weekend? I... Dad and mom miss you!"
  * "Nii-chan, don't you miss me at all? I'm sad :( "
  * "Ooo...of course, I… I... I MISS YOU! BOKE!"
  * Hangout with him and his team when you're back on the weekend. But he hates to see you dress up for his teammates.
  * "Tanaka senpai and Nishinoya senpai please don't ogle my sister!" "Y/N, I've told you don't wear this skirt, it's way too short!” said grumpy Kageyama when you don't give him a damn because you love how this skirt makes your legs look so damn long. Every time Kageyama will try to cover your legs with his jacket.
  * Tanaka and Nishinoya turn their attention to you after Shimuzu graduated. You actually think they are fun and smile at their exaggerated reaction every time. Which makes them swoon even more when seeing your smile.



Extra  
When Hinata found out you're in the national team of fencing, he became even more afraid of you and at the same time admire you. He worried that if he got Kageyama angry, you will stab him with a sword to get revenge for your brother. Until now you have no idea that why he is so jumpy around you.

**Notes for the Chapter:**

> I think we all agree that when Kageyama said BOKE, it means darling, sweetie, honey, love and etc ⁽⁽ ◟(∗ ˊωˋ ∗)◞ ⁾⁾


	4. Miya Atsumu and Miya Osamu

**Notes for the Chapter:**

> Warning: swear words and a little violence ahead

  * The three of you are inseparable. The twins especially Atsumu have a hard time letting you be alone. They always eat with you, go out with you, basically, they stick by your side all the time.
  * They insist that you go to school with them to their morning practice and wait for them to finish practice to go home together because they don't like the idea of you walking alone. Even though, you ensure them that you're perfectly fine walking alone to school because their morning practice is so damn early and you want to sleep. But of course, your protest is useless. So instead you just nap at the gym, using your bag as a pillow and their jersey as a blanket.  
P.S you sleep through Atsumu's killing jump serve even though the sound of the ball hitting the floor is deafening.
  * You only started to go with them willingly to their morning practice after that one time you really really want to sleep and refuse to leave your lovely bed. Your pervert brother Atsumu thought it was a good idea to help you get prepared for school. He carried you to the bathroom, make you sit on the bathroom counter. He then helped you to brush your teeth and wash your face. In your sleepy state, you were like oh that's mean I have more time to sleep, I'll just need to change to uniform when I wake up later. Then you felt a sudden chill on your chest, and there are hands meddling your pajamas top. You struggled to open your eyes, then you see Atsumu already unbutton half of your top. You looked down and saw that your top is half opened and you can actually see half of your boobs and upper abdomen. You screamed at Atsumu and slapped his hands away. And ~~purposely~~ accidentally kicked his shin. Oops.
  * “Tsumu, what the fuck are you doing”
  * "Ouch… Y/N, I thought I can help you to change into your uniform so that you can sleep longer. Also, I always know that you have big boobs, but damn they are **BIG**.”
  * " **GET THE FUCK OUT YOU HENTAI! 'SAMU, HELP! HELP!** "
  * "Hey, be quiet, everyone is sleeping." Atsumu covered your mouth with his hand, hold your two hands at your back with his other hand to prevent you from hitting him. Well, when Osamu ran in and witnessed the state you were in, saying that he is shocked would be completely an understatement. Osamu quickly dragged Atsumu out and asked what the fuck happened. After knowing his intention, as expected, Osamu scolds him and beat him so hard that he can't do his powerful jump serve or any spike that day.
  * They love shopping with you because they love dressing you up according to their preference. You're totally okay with it since you love having new clothes plus they'll pay for you.
  * Whenever you go to watch their games, Atsumu will glare at any guy dare to look at you or even comes near you and Osamu will sling a protective arm around you. Sometimes they'll be so extra that they said baby thanks for coming to see us loudly and kiss your forehead or cheeks or both.
  * Atsumu secretly scared away all the boys who tried to confess to you. But you don't know that since you don't have many friends as you always spend time with your brothers.
  * You have a movie marathon with the twins once a month, every month has a different theme. You and Osamu love horror movies the most, but Atsumu CAN'T handle horror movies at all. Everytime he will force you to sit between his lap and bear hug you. Sometimes when there's jump scare, you will touch his neck with your cold hand. The louder his scream is, the harder you laugh.



Extra

After the bathroom incident, you refuse to speak with Atsumu for a few days, he literally kneels down and hug you to beg for your forgiveness.


	5. Tendou Satori

  * To say that having Tendou Satori as brother is fun is a complete and utter understatement. This guy is a personification of interestingness.
  * Surprisingly you're a bigger prankster than him. You two prank your friends together. Often.
  * When you met the team for the first time, the guys immediately knew that you're Tendou's sister because of your red hair.
  * You are in the same class as Goshiki. He is your desk mate.
  * You immediately know why your brother loves to prank Goshiki because that guy is such an innocent sweetheart and believes everything you've said.
  * There's one time that Tendou and Ushijima accidentally witnessed you got confessed by a second-year senpai who you've sworn you never met before. Tendou asked Ushijima to "rescue" you from that awkward situation which made the whole thing got more awkward because Ushijima just stands beside you, asked the guy "who are you, and why are you talking to Y/N." *Cue Ushijima alpha aura and intense stares.
  * After a week there's a rumour about Ushijima is your boyfriend and how he is jealous when he saw some guy confessed to you. You're 100% sure that rumour is spread by your brother.
  * Since you live in the dorm as well, you often hang out with the volleyball team. They keep bugging you to join the volleyball club as manager since you know all of them very well. More importantly, they have noticed that Coach Washijo tends to be in a good mood whenever you're visiting their practice because you'll always have a good chat with the coach.



**Notes for the Chapter:**

> Next chapter will be our one and only owl boy Bokuto (,,・ω・,,)


	6. Bokuto Koutaro

  * You're in the same class as Akaashi. The first day you met him, you were mesmerized by his beauty. Like why this boy is so pretty, it's so unfair. You told Bokuto about him and he was like nooooo Y/N is mine, nobody can get my baby imouto's attention away from me. After he knew that guy is Akaashi, he got into emo mode and been silently staring at Akaashi for a whole week. After Akaashi found out the reason, he had to beg you to come to their practice and cheer besides the court saying something like "Nii-chan is so cool!" "Nii-chan's spike is so powerful!" "Nii-chan saiko!"
  * Like how the team baby Bokuto, he babies you. Literally and physically. Bokuto gets so touchy when he's with you, he will absentmindedly play with your hair, put his hand on your waist to pull you closer to him or make you sit on his lap, and kiss your cheeks or forehead when you're going back to class after lunch. If the team doesn't know better, they'll think you're his girlfriend.
  * You sometimes wonder if Bokuto took all the tall genes with him or else why are you almost 1 foot shorter than him. Bokuto will pat your head and says "Y/N's height is so cute, you don't need to be taller. Nii-chan will protect you."
  * You love cooking, so you always prepare bento for Bokuto as well.
  * Coach Takeyuki asked you to be in charge of the meal preparation during the Fukurodoni training camp because he has heard of your amazing cooking skill. The biggest other reason that he asked for you is that when you're present Bokuto is less likely to get into his emo mode.
  * You are in charge of notifying those who do extra practice when it's time for dinner before the kitchen closed. When Bokuto sees you, he stops everything and runs from the court to the door, picks you up, and nuzzles your face. "Hey hey hey, my daily dose of Y/N." "Nii-chan you're sweaty and gross, don't hug me. And guys, it's time for dinner. "
  * Kuroo and Akasshi are used to it, but Tsukishima was shocked, though he never showed it, he was staring. Hard.
  * "Nii-chan, put me down, people are staring."
  * "Hey hey hey, Tsukki, this is my sister. Isn't she adorable?" Bokuto proudly said. He still didn't put you down, but instead, let you sit on his arm.
  * "Ya, senpai, her height is "adorable", Tsukishima smirked at Y/N.
  * Well, this is not the first time someone has told you that you're short, you're quite used to it actually. Of course, you're not gonna cry just because of that. But you're not gonna let him make fun of your height just like that. So you've decided to make him guilty by faking tears. "I know I'm short. Don't need to be mean." You said then quickly hide your face in Bokuto's shoulder because you're on the verge of laughing out loud after seeing Tsukishima's stunned face when he saw your teary eyes.
  * Okay, maybe Kuroo and Akaashi saw you're smiling before you hide your face in Bokuto's shoulder and start shaking because you are holding your laughter. Since they are standing right behind Bokuto. Or else they wouldn't start that "Oya." "Oya Oya. Tsukishima you're so doomed."
  * “Y/N! Don't cry! TSU-KI-SHI-MA WHAT HAVE YOU DONE” Bokuto's voice is booming. Though you can't see his face you're sure that he is glaring dagger at Tsukishima. He keeps patting your head and soothe your back to comfort you, which is nice and you feel so safe in his arms. But he is a sweaty mess right now, and they gonna eat their dinner. So you're probably should end your mischief.
  * "Nii-chan, I'm alright. Let's have dinner now. The kitchen is going to close soon. I have left some stewed meats for you guys. Let's go Akaashi kun, Tetsu senpai. "
  * When you're walking out, you make sure you let Tsukishima sees your smirk and blowing a raspberry. His jaw-dropping reaction is priceless. You almost can’t hold your laughter.



Extra

For the rest of the training camp, Karasuno team has wonder why the hell when they against Fukurodani, Bokuto is so hyped up and make sure that on every match Fukurodani's score is almost doubled.

**Notes for the Chapter:**

> Not sure whether I should write Tanaka or Aone for the next chapter ( ˘•ω•˘ )  
> Feel free to request for any particular scenario you would like me to include in the future chapter~


End file.
